Performance of pigs kept under different sanitary conditions affected by protein intake and amino acid supplementation.

There is growing evidence that requirements for particular AA increase when pigs are kept under low sanitary conditions. The extent to which reduction in growth performance is related to these increased requirements is unclear. To evaluate this relationship, an experiment (2 × 2 × 2 factorial arrangement) was performed with 612 male pigs (9 per pen) kept under low sanitary conditions (LSC) or high sanitary conditions (HSC) and offered ad libitum access to either a normal CP concentration diet (NP; 17, 15, and 15% CP for the starter, grower, and finisher phase, respectively) or a low CP concentration diet (LP; 20% CP reduced relative to NP for each phase), each of which containing a basal AA profile (AA-B) or a supplemented AA profile (AA-S). The supplemented diet type contained 20% more Met, Thr, and Trp relative to Lys on an apparent ileal digestible basis compared with the basal diet type. Pigs were followed for a complete fattening period and slaughtered at a targeted pen weight of 110 kg. Haptoglobin concentrations in serum (0.92 g/L for LSC and 0.78 g/L for HSC) and IgG antibody titers against keyhole limpet hemocyanin (3.53 for LSC and 3.08 for HSC) collected in the starter, grower, and finisher phases and pleuritis scores at slaughter (0.51 for LSC and 0.20 for HSC) were greater for LSC pigs compared with HSC pigs ( ≤ 0.01), illustrating that sanitary conditions affected health conditions. The ADG and G:F were greater for HSC pigs compared with LSC pigs ( ≤ 0.01). The number of white blood cells (WBC) was higher in (AA-S)-fed pigs compared with (AA-B)-fed pigs when kept at LSC but not at HSC [SS (sanitary conditions) × AA interaction, = 0.04]. Pigs fed NP had a lower number of WBC compared with pigs fed LP ( = 0.02). The number of platelets in pigs fed AA-S diets was higher compared with pigs fed AA-B diets ( ≤ 0.01). A 20% reduction in dietary supplementation of Met, Thr, and Trp relative to Lys decreased G:F more in LSC pigs than in HSC pigs (interaction, = 0.03), illustrating that dietary requirements for these AA differ depending on sanitary conditions. This study, performed under practical conditions, shows that AA requirements are dependent on sanitary conditions. Furthermore, supplementation of diets with particular AA may improve performance, especially under poor hygienic conditions. Dietary protein concentration as well as Met, Thr, and Trp supplementation can modify immune status, which may influence resistance to subclinical and clinical diseases.

Effects of two different dietary fermentable carbohydrates on activity and heat production in group-housed growing pigs.

The effects of two sources of dietary fiber (DF) on behavior and heat production (HP) in group-housed growing pigs were studied. Twenty clusters of 14 barrows (50 kg) were fed one of 10 diets. Diets differed mainly in type and content of fermentable DF (fDF) and in content of digestible starch. Five diets contained solvent-extracted coconut meal (SECM) and five diets contained soybean hulls (SBH) as the main fDF source. On an as-fed basis, pigs received 3.5, 13.2, 23.0, 32.7, or 42.4 g x kg(-0.75) x d(-1) of SECM or SBH. A total of 280 crossbred growing pigs were used, divided into clusters of 14 pigs each. Pigs were group-housed and fed at 2.5 times the assumed maintenance energy requirements. All clusters were fed similar amounts of NE, ileal-digestible protein and amino acids, vitamins, and minerals. Consequently, DMI differed among diets because NE content decreased with increasing DF content. After a 32-d preliminary period, HP was measured per cluster during a 7-d experimental period in environmentally controlled respiration chambers. Behavior of the pigs was recorded using time-lapse video recordings during two different days within the experimental period. Intake of digestible starch and fDF was different (P < 0.001) among diets, whereas intake of digestible CP was similar among diets. On average, pigs spent 153 min standing, 42 min sitting, 202 min lying on their chest, and 1,043 min lying on their flanks each day. Pigs fed SECM diets spent, on average, less time (P < 0.05) lying on their chest than pigs fed SBH diets. Total time spent on physical activity (i.e., standing plus sitting, 195 min/d) was not affected by diet. Total HP and resting HP were affected by diet and were on average lower (P < 0.01) for pigs fed SECM diets than for pigs fed SBH diets. Activity-related heat production (AHP) averaged 65 kJ x kg(-0.75) x d(-1) and was not affected by diet. There was a linear relationship (P < 0.001) between fDF intake and HP, but there was no relationship between fDF intake and AHP. During different parts of the day, fDF intake also affected HP. The saving effect of physical activity on the NE values of fDF from SECM and SBH were 0.56 and 0.84 kJ/g of fDF intake, respectively. Neither of these saving effects was significantly different from zero. We conclude that fDF from SECM and SBH did not affect energy expended on physical activity by growing pigs, and that the NE value of fDF from SECM and SBH was not affected by changes in physical activity.

Effects of dietary fermentable carbohydrates on behavior and heat production in group-housed sows.

The effects of dietary nonstarch polysaccharides (NSP) on behavior and heat production in group-housed sows were studied. Twelve groups of six nonpregnant sows were fed one of four experimental diets that were similar in composition except for starch and NSP contents. Exchanging sugar beet pulp silage (SBPS) for tapioca created the difference in dietary starch and NSP ratio. On a dry matter (DM) basis, diets contained 0, 10, 20, or 30% SBPS. Sows were group-housed. Intake of fermentable NSP (fNSP) for diets containing 0, 10, 20, or 30% SBPS averaged 7.06, 9.18, 11.61, and 13.73 g x kg(-0.75) d(-1), respectively. Sows were fed, once a day at 0800. Dry matter intake for diets containing 0, 10, 20, or 30% SBPS, averaged 38.05, 38.38, 38.53, and 38.35 g x kg(-075) x d(-1), respectively, and ME intake averaged 523, 518, 514, and 493 kJ x kg(-0.75) x d(-1), respectively. On average, sows spent 177 min/d on physical activity, of which 8.8% was spent on eating. Time spent in physical activity was affected by diet (P = 0.005). Sows fed 0 or 10% SBPS spent more time on physical activity than sows fed 20 or 30% SBPS (P = 0.002). Energy cost of physical activity averaged 464 kJ x kg(-0.75) x d(-1) (standard estimated mean of 31) and was similar for diets (P = 0.679). Total heat production (HP) and activity-related heat production (AHP) were affected by diet (P < 0.05). Sows tended to be quieter when fNSP intake increased (P = 0.063). The effect of fNSP intake on HP and AHP was not constant during the day. During the night period, fNSP intake did not affect HP and AHP (P > 0.10). During the day period, increased fNSP intake decreased HP (P = 0.006) and tended to decrease AHP (P = 0.062). During eating, increased fNSP intake increased HP (P = 0.012) and tended to increase AHP (P = 0.074). Despite similar DMI, sows fed 0 or 10% SBPS spent less time eating than sows fed 20 or 30% SBPS (P = 0.009). Feed consumption rate was higher (P = 0.003) in groups fed 0 or 10% SBPS than in groups fed 20 or 30% SBPS. Feed consumption rate decreased by 0.19 g DM x kg(-0.75). min(-1) (P = 0.003) for each gram of fNSP intake. The energy saving effect of physical activity on the NE value of fNSP from SBPS ranged between 2.3 and 3.7 kJ/g of fNSP intake. In conclusion, intake of fNSP from SBPS affected energy expenditure for physical activity (P = 0.063); however, this effect was not constant during the day.

Fermentation of liquid coproducts and liquid compound diets: Part 1. Effects on chemical composition during a 6-day storage period.

The effects of a 6-day storage period on changes in dry matter, crude ash, crude protein, true protein, crude fat, starch, soluble starch, sugar and lactose of three liquid coproducts and two liquid compound diets were studied. The three liquid coproducts studied were: liquid wheat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW), and the two liquid compound diets were: liquid grower diet (LGD) and liquid finisher diet (LFD). The loss of corrected dry matter after a 6-day storage, expressed in relation to the initial content, was 1.9, 6.2, 9.6, 4.6 and 4.2% for LWS, PSP, CW, LGD and LFD, respectively. During storage, the total amount of starch decreased 2.7, 24.0, 28.1 and 33.3% for LWS, PSP, LGD and LFD, respectively. The total amount of lactose decreased 23.5% for CW. The gross energy value of the products did not change remarkably during the 6-day storage period; gross energy losses being less than 3% of the initial gross energy content.

Fermentation of liquid coproducts and liquid compound diets: Part 2. Effects on pH, acid-binding capacity, organic acids and ethanol during a 6-day storage period.

The effects of a 6-day storage period on changes in pH, acid-binding capacity, level of organic acids and ethanol of three liquid coproducts [liquid wheat starch (LWS), mashed potato steam peel (PSP) and cheese whey (CW)] and two liquid compound diets [liquid grower diet (LGD) and liquid finisher diet (LFD)] were studied. All products, except LWS, showed a significant decrease in pH and acid-binding capacity during storage. At the end of the storage period, all products reached a pH of between 3.5 and 3.9. In general, it can be concluded that the lactic acid content, and to a lesser extent the acetic acid content, increased dramatically during storage. In contrast, the ethanol content increased significantly in the liquid compound diets only. The pattern of changes in pH and organic acids during the 6-day storage period was different between the liquid coproducts and the liquid compound diets. At the start of storage, liquid coproducts are already in the 'middle' of the fermentation process, while liquid compound diets need approximately 24-36 h before fermentation begins. Consequently, in practice a different approach to obtain fermented diets is needed for liquid coproducts and liquid compound diets.

Effects of dietary fermentable carbohydrates on energy metabolism in group-housed sows.

The effect of dietary nonstarch polysaccharide (NSP) content on the metabolic rate in group-housed sows was studied. Twelve groups of six nonpregnant sows were each fed one of four experimental diets similar in composition except for the starch and NSP content. Exchanging sugar beet pulp silage (SBPS) for tapioca created the difference in starch and NSP ratio in the diet. On a DM basis, diets contained 0, 10, 20, or 30% SBPS. Sows were group-housed and fed at 1.30 times the assumed maintenance energy requirements. Nitrogen and energy balances were measured per group during a 7-d experimental period, which was preceded by a 33-d adaptation period. Both digestibility and metabolizability of energy decreased with increasing dietary SBPS content (P < 0.05). Heat production and energy retention were unaffected by the exchange of starch for NSP (P > 0.1). Based on energy retention data and apparent fecal digestibilities of crude protein, crude fat, starch, and NSP, the estimated net energy value of fermented NSP was 13.4 kJ/g. The present study shows that group-housed sows are capable of using energy from fermented NSP (i.e., NSP from SBPS) as efficiently as energy from digested starch (i.e., starch from tapioca).